1. Field of the Invention
The present invention relates to an x-ray apparatus for medical radiology. More specifically, the invention relates to an x-ray apparatus for mammography, including receiving tomosynthesis data and obtaining radiological images in galactography (see, e.g., U.S. Pat. No. 6,480,566 which is incorporated by reference herein) and angiography. This invention also can be used in computer tomography.
2. Background Art
Mammography is a tool for diagnosing breast cancer. Images of a tumor can be viewed on film or (if it is used a digital detector) on a computer screen. Successful treatment of breast cancer depends on early diagnosis. Mammography plays a central part in early detection because it can show changes in the breast up to two years before a patient or physician can feel them. Due to mammography in the United States, the death rate from breast cancer has dropped almost 20% in the past decade, after having been stable for the prior 50 years (Nass, SJ et al, Mammography and Beyond: Developing Technologies For the Early Detection of Breast Cancer, National Academy, pp. 18–19, 2001).
X-ray apparatus for mammography currently exists. It has a typical distance of about 65 cm between the focal spot of an x-ray source and a top paddle. In mammography, the physician would like to have the focal spot of the x-ray source as close as possible to the sternum of a patient to be examined, and thus over the free end—representing the exposure side of the x-ray examination system—of a support provided for the breast of the patient. This permits irradiation of the tissue to be examined as completely as possible, since the x-rays emanate from the focal spot and include the base of the breast, i.e., that region of the breast that forms the transition to the rib cage.
There is also a desire in computed tomography to have the exposure plane, i.e., the plane of the body layer to be exposed, and thus the focal spot of the x-ray source, as close as possible to the actuation side of a gantry, i.e., that side of the gantry at which the physician is located for preparation of the exposure and possibly during examination. The actuation side of the gantry is usually provided with control and/or display elements.
Although mammographic screening for breast cancer has proved invaluable in the early detection and diagnosis of breast cancer, conventional mammography does not detect all cancers. As many as 20% of the cancers that become evident during one year would not have been visible at screening mammography procedures performed within that year. A major factor contributing to this situation is the “structured noise” created by the overlap of normal structures, which are superimposed on each other in the acquisition of a two-dimensional mammographic projection. This recognition has prompted recent interest in breast tomosynthesis. Breast tomosynthesis acquires multiple images as the x-ray source moves through an arc above the stationary compressed breast and digital imaging detectors. In turn, this creates a need for a monochromatic, easily movable, small size, x-ray source which can be placed in close proximity to the examined tissue.
There exists an x-ray apparatus, including an x-ray source, which can be placed above a top paddle or even implanted into a patient's body for directly irradiating a desired region of tissue with the x-rays (e.g., U.S. Pat. No. 6,580,940 issued to G. Gutman, which is incorporated by reference). That apparatus delivers monochromatic, low energy x-ray radiation to the examined tissue from an easily movable, small size focus x-ray source.